Few studies have employed multimodal measureZ01MH02395 in the same autistic individual, thus considerable reducing their power. The current proposal will attempt to use cerebral blood flow, magnetic resonance imaging, and neuropsychology to provide convergent evidence as to the source of the deficit in autism. In this study, autistic individuals would be presented with cognitive tasks and affect laden tasks in order to challenge various brain regions. Activation will then be correlated with brain structures that were imaged on MR scans as well as results of neuropsychological tests tapping attention, memory, procedural abilities, language, and visual spatial functions. By utilizing autistic individuals with savant skills, we hope not only to gain greater understanding of the neurobiology of exceptional performance, but increased "signal-to-noise" ratio in the autistic population. Autistic individuals without savant skills and mentally retarded individuals, as well as normals, will serve as controls.